Right now, NASAs Perseverance rover is flying through space toward a February landing on Mars, and no one is watching closer than Dr. Caleb Fassett of Huntsvilles Marshall Space Flight Center. Fassett wrote the scientific paper almost 20 years ago that gave Perseverance its destination.

Fassetts research found evidence that the crater - since named Jezero Crater - once held a lake and has good odds of holding signs of ancient life on the Red Planet. NASA has bet the $3 billion mission cost that Fassett and the scientists who share his view are right. And NASA upped the ante. For the first time, a rover will try to send samples from the planet back to Earth.

This particular place on Mars was something I had spotted in very low-resolution data in 2003, 2004, Fassett said last week. In that data, it was really clear that there were these valleys in this crater. What Fassett saw in images from the Mars Odyssey spacecraft, which is still orbiting Mars, were signs of sedimentary deposits on one side of the crater and an outlet on the other side. To have an outlet form, you have to fill the whole (crater) up and have it overflow, Fassett said. That basically demands the existence of a lake.

That was exciting when I found it initially, Fassett said. Its gotten cooler since then.

This map shows regions in and around Jezero Crater on Mars, the landing site of NASA's Perseverance rover. The green circle represents the rover's landing ellipse. Jezero held a lake and river delta billions of years ago; scientists want to capture samples of rock in these regions that may contain evidence of ancient microscopic life, which will be returned to Earth by a future mission for extensive study.

In a study led by colleague Bethany Ehlmann, Fassett also was part of a team that discovered carbonate in the crater, a mineral that requires relatively moderate conditions to form. A lot of the carbonates on Earth, the reason they (form) is because of organisms, Fassett said. You can also get them to precipitate inorganically without biology at all, and that may very well be the case with these Mars ones.

Scientists have seen this before. Carbonates were found in a rock sample from a Martian meteorite that hit Earth, Fassett said, and that was one of the things that set off the Mars program re-invigoration in the 1990s, because people were arguing it was biology.

Scientists dont think that now, he said, and Fassett believes finding evidence of life on Mars next year is unlikely. The rover is very capable, he said, but we have a hard time on Earth identifying the signatures of life in 3 billion-year-old rocks. Youve got to be very lucky, and people will argue about it in the literature for decades. So, the idea were going to send a robot that is going to solve this problem I think is actually unlikely.

Thats why NASA is looking at the big step of bringing samples back to Earth. Scientists are skeptical, Fassett said, and if were going to convince scientists, its going to be (with) samples that are returned. I could be wrong. There could be a fossil I just dont think its very likely.

The plan is that if Perseverance finds interesting samples, they will be gathered and stored in the rover until a Mars Ascent Vehicle arrives later in the 2020s.

his illustration shows a concept of how the NASA Mars Ascent Vehicle, carrying tubes containing rock and soil samples, could be launched from the surface of Mars in one step of the Mars sample return mission.

The return mission will be a partnership with the European Space Agency. It includes a fetch rover to land on Mars and retrieve the samples from Perseverance and then transfer them to a return rocket that will launch them into Mars orbit. Another spacecraft in orbit will collect the samples and return them to Earth.

All of this will be expensive, complicated and take time, but it will be cheaper by billions of dollars, far faster and less complicated than the first flight of humans to the planet. And it could answer the fundamental question of life beyond Earth. We havent found life anywhere else in the Universe except Earth, Fassett said, so the first time were going to have to be very conscious to make a case for it. That would be a paradigm shifting discovery.

Fassetts discovery and the long wait to test it is part of the story of space exploration. One of the things you get used to as you explore other planets is the possibility that your findings are going to be hard to test further, he said. There was no guarantee when I was working on this in 2004, 2005 that wed ever go to this place on Mars. Mars has the land area of all the continents of the Earth put together. So, the odds you just pick one particular spot and thats where youre going to go, you have to get pretty lucky to follow up on your observations to go there.

Dr. Caleb Fassett is a planetary scientist at NASAs Marshall Space Flight Center. Originally from Maryland, Dr. Fassett earned his BS from Williams College in 2002, and MS and PhD from Brown University in 2005 and 2008, respectively.

Its not just patience, he said. Its also luck that allows us to push the envelope on this particular location.

Would he like to go to Mars to see for himself? I think given the chance, I probably would, Fassett said. Im pretty risk averse, so I dont know if Im the guy that would be your first choice as an astronaut. I think the reason we get the people we get is a certain tolerance for well-chosen risk.

I love the fact we can build these robots to be our explorers in the distant part of the universe without us having to be there to breathe and keep fed and come back, hopefully, he said. So, yeah, I hope 50 years from now people are doing space travel more routinely, but Im not personally going to go there.

Probably, he added.

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Mission to the Red Planet from NASA in Alabama - AL.com